Answer:
8% tax rate.
Step-by-step explanation:

The 8% (0.08) is the tax rate because the 100%, or 1.00, is the original price of the racket, which was $13.
Answer:
$7,000
Step-by-step explanation:
Let
equal the original price.

Combine like terms.

Divide by the coefficient of
, which in this case is 

If you like the variable on the left, rewrite:

You could make a small (easily repaired) leak and watch it for the amount of time you need to conclude what you need to.
Answer:
118.125 lb
Step-by-step explanation:
0=2.25
H=6.5 x O
H=6.5 x 2.25
H=14.625
H+O=2.25+14.625=16.875 per day
16.875x7 days=118.125 lb